This invention relates to a machine tool having a tool-changing device, which has a working spindle with a spindle head to accept a rotating tool in the form of an exchangeable tool block and a releasable clamping device for clamping the tool block to the spindle head, the tool changing device being provided with a double-sided changing arm, which, for tool transfer between the spindle head and a tool magazine, is provided with a tool gripper at each of its two ends and is pivotable about a pivoting axis parallel to the spindle axis.